Fixed RtlCompareString and RtlCompareStringN, they were very wrong, for CompareString the params are struct ptrs not char ptrs

Fixed a ton of clang-cl compiler warnings about unused variables, still many left. Fixed a lot of inconsistent override ones too

src/xenia/gpu/d3d12/d3d12_command_processor.cc

@@ -5152,6 +5152,7 @@ void D3D12CommandProcessor::WriteGammaRampSRV(
 #define COMMAND_PROCESSOR D3D12CommandProcessor
 
 #include "../pm4_command_processor_implement.h"
+#undef COMMAND_PROCESSOR
 }  // namespace d3d12
 }  // namespace gpu
 }  // namespace xe